Interventional cardiologists and radiologists currently practice a wide range of procedures that require percutaneous access to the human vascular system. In many of these procedures, percutaneous access occurs at the site of the common femoral artery or vein at the groin for the purpose of passing guide wires and introducer sheaths. Catheters can then be advanced through these sheaths to many places within the human vascular system.
One method for performing this procedure utilizes a hollow steel cannula with a separate sharpened stylet needle through its center which is pushed through skin and then completely through the common femoral artery. The stylet is then removed and the steel cannula is pulled back slowly until blood under arterial pressure squirts vigorously in a pulsatile manner out of the cannula's proximal end thus indicating that the cannula's distal end is properly placed within the artery. A guide wire is then placed through the cannula and advanced into the artery, and then the cannula is pulled out. A variety of introducer sheaths and/or catheters can then be advanced over the guide wire and into the arterial system.
Another method for accessing arteries is by means of an introducer needle with a sharpened distal end that does not use a stylet needle. This introducer needle is placed through the skin at the groin and advanced until the opening of its sharpened distal end lies within the arterial lumen. When this occurs, blood squirts forcibly in a pulsatile manner out of the needle's proximal end. The pulsatile blood flow indicates that the introducer needle is properly located in the artery so that a guide wire can be inserted through the introducer needle.
One disadvantage of existing needles is that they have a short, square cross section, optically opaque, plastic handle (or body) which is not comfortable to hold when pushing the needle's sharpened distal end through skin and tissue at the groin. In fact, a typical plastic handle would be approximately 0.8 inches long and would have sharp corners molded into the plastic which are not comfortable to hold while applying considerable squeezing force between the thumb and forefinger while inserting the needle.
Furthermore, because of their short length and opaque body, one cannot see the blood before it squirts out of the needle (when the tip is placed in an artery) until the blood is actually squirting out. The blood squirting out of the cannula at arterial pressure results in a considerable release of blood which can find its way into the eyes, nose, or other mucosal membranes of health care workers in close proximity to the patient. Besides being messy and causing unnecessary blood loss to the patient, the squirted out blood represents a risk to the health care workers who could be exposed to infectious diseases such as HIV carried in the patients blood. Thus minimizing the blood squirting out of the proximal end is highly desirable.
Furthermore, no existing vascular access needles have an indicator as to the angle of the plane of the opening at the needle's distal end. Still further, existing vascular access needles require a separate syringe to be joined at their proximal end in order to create a suction when accessing veins. When accessing the jugular vein in the neck it is sometimes difficult to tell if the needle has accidentally penetrated the carotid artery instead of the hemostasis valve which causes an undesirable drag force on the guide wire as it is inserted into the blood vessel.